Self-calibrating ultrasonic removal of ectoparasites from fish

ABSTRACT

Methods, systems, and apparatus, including computer programs encoded on computer-storage media, for self-calibrating ultrasonic removal of sea lice. In some implementations, a method includes generating, by transducers distributed in a sea lice treatment station, a first set of ultrasonic signals, detecting a second set of ultrasonic signals in response to propagation of the first set of ultrasonic signals through water, determining propagation parameters of the sea lice treatment station based on the second set of ultrasonic signals that were detected, obtaining an image of a sea louse on a fish in the sea lice treatment station, determining, from the image, a location of the sea louse in the sea lice treatment station, and generating a third set of ultrasonic signals that focuses energy at the sea louse.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a continuation (and claims the benefit ofpriority under 35 USC 120) of U.S. patent application Ser. No.17/132,874, filed Dec. 23, 2020. The disclosure of the prior applicationis considered part of (and is incorporated by reference in) thedisclosure of this application.

TECHNICAL FIELD

This specification relates to ultrasound devices that are used in thecontext of aquaculture.

BACKGROUND

Sea lice are parasites that can create significant problems for farmedfish. When sea lice attach themselves to fish, they feed on fish'snatural mucus, which causes lesions to form. Such lesions may reduce themarketability of farmed fish, and can even cause farmed fish to die.Moreover, if sea lice are too plentiful on a farm, it can cause the farmto be required to shut down because of the effects on wild populations.

Sea lice may be extremely difficult to remove, as the sea lice are onlya few millimeters long and may suction themselves very strongly onto theskin of fish. Removal can be even more difficult when sea lice embedthemselves within the mucus of host fish or between fish scales.

SUMMARY

In general, innovative aspects of the subject matter described in thisspecification relate to a self-calibrating device that is used for theultrasonic removal of parasites such as sea lice. Sea lice may beremoved or loosened from fish using ultrasonic signals. For example,ultrasonic signals may be used to generate cavitation bubbles that formunder and around sea lice, allowing water rushing past the fish andnatural motion of fish to dislodge the lice. Ultrasonic signals, evenwithout cavitation bubbles, may also traverse along sea lice to sweepthe sea lice off fish. Additionally, ultrasonic signals may break acarapace of sea lice so that freshwater or another substance lethal onlyto the lice may penetrate and kill the sea lice, or damage/disablereproductive capability.

However, because ultrasonic signals could potentially damage or descalefish, the enhanced techniques described by this specification mayspecifically focus energy on sea lice instead of fish. Because targetingof ultrasonic signals may be difficult, as ultrasonic signals propagatedifferently in water based on many factors such as water temperature,water pressure, water chemistry, concentration of fish mucus, andconcentration of excrement, repeated self-calibration by the device mayenable more accurate targeting. For example, temperature changes alonemay cause ultrasonic signals to converge at locations that arecentimeters apart and a sea lice may only be millimeters long, sorepeated self-calibration may allow the device to determine differentultrasonic signals that converge at a particular location that may bemost effective for louse elimination as temperatures change.

To account for changes in propagation, a sea lice treatment station mayuse self-calibrating ultrasonic removal of sea lice. The sea licetreatment station may include many ultrasonic transducers that aredistributed throughout the sea lice treatment station. The sea licetreatment station may continually perform self-calibration to determinepropagation parameters that take into account how ultrasonic signalspropagate through water within the sea lice treatment station at themoment of treatment. When the sea lice treatment station detects a sealouse on a fish, the sea lice treatment may use the propagationparameters to generate ultrasonic signals that focus energy at or nearthe sea louse. Accordingly, the sea lice treatment station may useultrasonic signals to safely remove sea lice from fish.

One innovative aspect of the subject matter described in thisspecification is embodied in a method that includes generating, byultrasonic transducers distributed in a sea lice treatment station, afirst set of ultrasonic signals, detecting, by the ultrasonictransducers, a second set of ultrasonic signals in response topropagation of the first set of ultrasonic signals through water in thesea lice treatment station, determining propagation parameters of thesea lice treatment station based on the second set of ultrasonic signalsthat were detected, obtaining an image of a sea louse on a fish in thesea lice treatment station, determining, from the image, a location ofthe sea louse in the sea lice treatment station, and generating, by theultrasonic transducers and based on the propagation parameters and thelocation of the sea louse in the sea lice treatment station, a third setof ultrasonic signals that focuses energy at the sea louse.

A second innovative aspect of the subject matter described in thisspecification is embodied in a method that includes generating, byultrasonic transducers distributed in a sea lice treatment station, afirst set of ultrasonic signals, detecting, by the ultrasonictransducers, a second set of ultrasonic signals in response topropagation of the first set of ultrasonic signals through water in thesea lice treatment station, determining propagation parameters of thesea lice treatment station based on the second set of ultrasonic signalsthat were detected, and storing the propagation parameters for latertreatment of sea lice.

A third innovative aspect of the subject matter described in thisspecification is embodied in a method that includes obtaining an imageof a sea louse on a fish in a sea lice treatment station, determining,from the image, a location of the sea louse in the sea lice treatmentstation, accessing propagation parameters of the sea lice treatmentstation from storage of the sea lice treatment station, and generating,by ultrasonic transducers of the sea lice treatment station and based onthe propagation parameters and the location of the sea louse in the sealice treatment station, a third set of ultrasonic signals that focusesenergy at the sea louse.

A fourth innovative aspect of the subject matter described in thisspecification is embodied in a method that includes generating, byultrasonic transducers distributed in a ectoparasite treatment station,a first set of ultrasonic signals, detecting, by the ultrasonictransducers, a second set of ultrasonic signals in response topropagation of the first set of ultrasonic signals through water in theectoparasite treatment station, determining propagation parameters ofthe ectoparasite treatment station based on the second set of ultrasonicsignals that were detected, obtaining an image of an ectoparasite on afish in the ectoparasite treatment station, determining, from the image,a location of the ectoparasite in the ectoparasite treatment station,and generating, by the ultrasonic transducers and based on thepropagation parameters and the location of the ectoparasite in theectoparasite treatment station, a third set of ultrasonic signals thatfocuses energy at the ectoparasite.

Other implementations of this and other aspects include correspondingsystems, apparatus, and computer programs, may be configured to performthe actions of the methods, encoded on computer storage devices. Asystem of one or more computers can be so configured by virtue ofsoftware, firmware, hardware, or a combination of them installed on thesystem that in operation cause the system to perform the actions. One ormore computer programs can be so configured by virtue of havinginstructions that, when executed by data processing apparatus, cause theapparatus to perform the actions.

The foregoing and other embodiments can each optionally include one ormore of the following features, alone or in combination. For instance,in some aspects generating a third set of ultrasonic signals thatfocuses energy at the sea louse includes determining, from the image,that a portion of the fish is not between a particular ultrasonictransducer and the sea louse and based on determining, from the image,that the portion of the fish is not between the particular ultrasonictransducer and the sea louse, generating an ultrasonic signal of thethird set of ultrasonic signals with the particular ultrasonictransducer. In certain aspects, generating a third set of ultrasonicsignals that focuses energy at the sea louse includes determining, fromthe image, that a portion of the fish is between a particular ultrasonictransducer and the sea louse and based on determining, from the image,that the portion of the fish is not between the particular ultrasonictransducer and the sea louse, determining not to generate an ultrasonicsignal with the particular ultrasonic transducer.

In some implementations, detecting, by the ultrasonic transducers, asecond set of ultrasonic signals in response to propagation of the firstset of ultrasonic signals through water in the sea lice treatmentstation includes detecting, by a first ultrasonic transducer, ultrasonicsignals in response to propagation of a first ultrasonic signal that wasgenerated by a second ultrasonic transducer and detecting, by the firstultrasonic transducer, ultrasonic signals in response to propagation ofa second ultrasonic signal that was generated by a third ultrasonictransducer after the first ultrasonic signal was generated. In someaspects, determining propagation parameters of the sea lice treatmentstation based on the second set of ultrasonic signals that were detectedincludes determining at least one of: width of ultrasonic signals of thesecond set of ultrasonic signals, time offsets between detections of thesecond set of ultrasonic signals and generation of the first set ofultrasonic signals, or reflections of the first set of ultrasonicsignals.

In certain aspects, actions include obtaining sensor data from at leastone of a water temperature sensor, a water pressure sensor, or a watersalinity sensor, where determining propagation parameters of the sealice treatment station is based on the sensor data and the second set ofultrasonic signals that were detected. In some implementations,generating, by the ultrasonic transducers and based on the propagationparameters and the location of the sea louse in the sea lice treatmentstation, a third set of ultrasonic signals that focuses energy at thesea louse includes determining phases of continuous wave ultrasonicsignals in the third set of ultrasonic signals. In some aspects,generating, by the ultrasonic transducers and based on the propagationparameters and the location of the sea louse in the sea lice treatmentstation a third set of ultrasonic signals that focuses energy at the sealouse, includes determining time delays of pulsed ultrasonic signals inthe third set of ultrasonic signals. In some implementations, actionsinclude determining that ultrasonic signals generated by a particularultrasonic transducer satisfy self-cleaning criteria and based ondetermining that ultrasonic signals generated by the particularultrasonic transducer satisfy self-cleaning criteria, generating, by theultrasonic transducers, a fourth set of ultrasonic signals that focusenergy at the particular ultrasonic transducer.

The above-noted aspects and implementations further described in thisspecification may offer several advantages. For example, the device mayremove sea lice off fish with less damage to the fish than existing sealice removal solutions. In another example, the device may reduce anamount of energy used by more efficiently directing ultrasound energy atsea lice. In yet another example, the device may increase the health offish being raised in aquaculture environments. In still another example,the device may work in a larger range of environmental conditions (e.g.,temperatures, water chemistries, station geometries, etc.).

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will become apparent from the description,the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an example of a sea lice treatment system.

FIGS. 2A and 2B are diagrams showing an example sea lice treatmentstation.

FIG. 3 is a diagram showing an example of a sea lice treatment system.

FIG. 4 is a flow diagram illustrating an example of a process forself-calibrating ultrasonic removal of sea lice.

FIG. 5 is a diagram showing a sensitive area around an eye and gills offish.

Like reference numbers and designations in the various drawings indicatelike elements. The components shown here, their connections andrelationships, and their functions, are meant to be exemplary only, andare not meant to limit the implementations described and/or claimed inthis document.

DETAILED DESCRIPTION

FIG. 1 is a diagram showing an example of a sea lice treatment system100. While the sea lice treatment system 100 is described in variousexamples as treating sea lice, the sea lice treatment system 100 maysimilarly be used to treat other ectoparasites that attach to fish, asdescribed further below. The system 100 includes a fish tank 101 and asea lice treatment station 102 connected to the fish tank 101. A waterpump 103 helps circulate the water of the fish tank 101.

A dotted outline of the first fish 109 is used to illustrate that thefirst fish 109 is inside the sea lice treatment station 102. Analternative view of the sea lice treatment station 102 and the fishbeing treated for sea lice is presented in FIGS. 2A and 2B. A secondfish 110 and a third fish 111 (and perhaps other fish) swim within thefish tank 101. The fish 109 may be placed in the fish tank 101, and maybe observed, by a worker 115.

A visual cutout 104 d is used to show internal elements of the sea licetreatment station 102. The sea lice treatment station 102 includes acamera 104 and ultrasonic transducers 106 a, 106 b (collectivelyreferred to as 106). While only two ultrasonic transducers 106 are shownin FIG. 1 , the sea lice treatment station 102 may include one hundred,two hundred, or some other number of ultrasonic transducers 106.

The ultrasonic transducers 106 may generate ultrasonic signals anddetect ultrasonic signals. For example, the ultrasonic transducers 106may be ultrasonic transceivers, or a combination of ultrasonictransmitters that emit ultrasonic signals and ultrasonic receivers thatsense ultrasonic signals. The camera 104 is shown between the ultrasonictransducers 106. However, the camera 104 may be before the ultrasonictransducers 106 in the direction of water flow, or after ultrasonictransducers 106. While only a single camera is shown, the sea licetreatment station 102 may include multiple cameras to detect sea lice,and may also include lights.

A control unit 112 of the system 100 interfaces with elements includingthe sea lice treatment station 102. The control unit 112 may includedigital electronic circuitry that forms an ultrasonic calibrator, a sealice detector, and a sea lice treatment controller. The ultrasoniccalibrator may determine propagation parameters of the sea licetreatment station 102. For example, the ultrasonic calibrator mayperform self-calibration for a period of five minutes every hour, once aday at a particular time, or some other frequency. Additionally oralternatively, the sea lice treatment station 102 may perform theself-calibration whenever no fish are inside the sea lice treatmentstation 102. For example, the sea lice treatment station 102 maycontinue to perform self-calibration until a fish is detected about toenter the sea lice treatment station 102 by object detection on an imagefrom the camera 104, pause self-calibration while the fish is inside thesea lice treatment station 102, and resume self-calibration once the sealice treatment station 102 detects that the fish has exited the sea licetreatment station 102.

Propagation parameters may reflect how ultrasonic signals propagatethrough water within the sea lice treatment station 102. For example,propagation parameters may specify at least one of: pulse width ofultrasonic signals sensed by the ultrasonic transducers 106, timeoffsets between when ultrasonic signals were generated and sensed by theultrasonic transducers 106, reflections of ultrasonic signals within thesea lice treatment station 102, spectral width of ultrasonic signalssensed by the ultrasonic transducers 106, or phase offset.

The sea lice detector may obtain images from the camera 104 and detectsea lice on fish. For example, the sea lice detector may detect a sealouse on one side of a tail of the fish 109. The sea lice treatmentcontroller may, based on the propagation parameters, generate ultrasonicsignals that focus energy on the sea louse that was detected. Forexample, the sea lice treatment controllers may determine differentultrasonic signals to be generated by different ones of the ultrasonictransducers 106, where energy of the signals converges so the locationwith highest energy is at the sea louse.

Stages A-C of FIG. 1 depict an example of the operation of the system100. Specifically, in stage A, before the fish 109 enters to sea licetreatment station 102, the ultrasound calibrator generates and sensesultrasonic signals by the ultrasonic transducers 106 and determinespropagation parameters from the ultrasonic signals sensed. The sensedultrasonic signals may be directly transmitted signals or reflectedsignals.

In stage B, the first fish 109 swims into the sea lice treatment station102. When the fish 109 is within the field of view of the camera 104,the sea lice detector may receive images of the fish 109 and use objectrecognition to detect sea lice on the fish 109. For example, the sealice detector may detect a sea louse on a tail of the fish by performingimage-based object recognition on one or more images from the camera104.

In stage C, the sea lice treatment controller may determine a set ofultrasonic signals that, when generated by the ultrasonic transducers106, focuses energy on the location of the sea louse within the sea licetreatment station 102. For example, the sea lice treatment controllermay determine to only generate ultrasonic signals on thirty of twohundred ultrasonic transducers 106, where the ultrasonic signals aredifferent from one another and converge most energy at the location ofthe sea louse.

In some implementations, stages B and C may repeat until all sea liceare removed or loosened from the fish 109. For example, stages B and Cmay repeat once every one fifty milliseconds while the fish 109 iswithin the sea lice treatment station 102. In another example, stages Band C may be performed once each time the fish 109 passes through thesea lice treatment station 102. In some implementations, the energyfocused on the sea louse may be increased until the sea lice detector nolonger detects the sea louse on the fish or a maximum energy limit thatis safe for fish is reached.

After sea lice treatment in the sea lice treatment station 102 takesplace, the first fish 109 may exit the sea lice treatment station 102and resume swimming freely within the fish tank 101. Further detectionsby the system 100 can take place concerning the second fish 110 afterthe second fish 110 swims around the fish tank 101 and into the sea licetreatment station 102. Once the second fish 110 is within the sea licetreatment station 102, the sea lice treatment station 102 can treat thesecond fish 110 for sea lice in a similar manner to discussed above inreference to the first fish 109.

In some implementations, the sea lice treatment system 100 may notinclude a camera. The sea lice treatment system 100 might be so gentlethat ultrasonic signals may provide ultrasonic energy all over the fish,or the sea lice treatment system 100 might always target behind theadipose and dorsal fins where lice is most commonly found. For example,the sea lice treatment system 100 may detect the presence, location,size, and orientation of fish based on changes in ultrasonic signalssensed by the ultrasonic transducers 106 and then, without attempting todetect sea lice on the fish, transmit ultrasonic signals with theultrasonic transducers 106 according to the propagation parameters thattarget a predetermined amount of ultrasonic energy at the adipose anddorsal fins.

FIGS. 2A and 2B are diagrams showing an example sea lice treatmentstation. FIG. 2A shows a side view of the sea lice treatment station 102and FIG. 2B shows a cross-sectional view of the sea lice treatmentstation 102. A shown in FIG. 2A, the sea lice treatment station 102 mayinclude ultrasonic transducers 106 a-106 h distributed along the top andbottom of the sea lice treatment station 102. FIG. 2B shows that theultrasonic transducers 106 b, 106 f, and 106 i-106 p may be distributedalong four walls of the sea lice treatment station 102. However, the sealice treatment station 102 may have other geometries. For example, thesea lice treatment station may be cylindrical with ultrasonictransducers distributed along a single inner wall or shaped as anoctogon with ultrasonic transducers distributed along eight walls.

For example, for a sea louse located on the left of the fish as shown inFIG. 2B, the sea lice treatment controller may receive x, y, zcoordinates of the sea louse in the sea lice treatment station 102 fromthe sea lice detector, determine a position of the fish 109 based onimages from the camera 104, and determine a particular combination ofultrasonic signals to be generated by only ultrasonic transducers 106 b,106 f, and 106 k.

The sea lice treatment controller may determine the ultrasonic signalsto generate based on obtaining stored propagation parameters for each ofthe ultrasonic transducers 106 a-106 p and calculating a combination ofultrasonic signals to be generated by the ultrasonic transducers thatincreases ultrasonic energy at the location of the sea louse relative toother locations in the sea lice treatment station 102, especially wherethe fish is located.

For example, the sea lice treatment controller may determine to generateparticular ultrasonic signals at only ultrasonic transducers 106 b, 106f, and 106 k. The determination may be based on determining thataccording to the propagation parameters for all of the ultrasonictransducers 106 a-106 p that the combination of the particularultrasonic signals are expected to propagate to focus more energy at thesea louse, while maintaining a safe amount of energy at the fish, thanany other combination of ultrasonic signals.

As mentioned in FIG. 1 , the propagation parameters for the ultrasonictransducers 106 a-106 p may be determined during a periodic calibrationbefore the fish 109 enters the sea lice treatment station 102. Forexample, the ultrasonic calibrator may, for each of the ultrasonictransducers 106 a-106 p, iteratively generate ultrasonic signals atdifferent frequencies, pulse duration, signal duration, and amplitudes,and detect the ultrasonic signals at the other transducers to determinepropagation parameters for the ultrasonic transducer that transmittedthe ultrasonic signals. The determination of propagation parameters andcalculation of ultrasonic signals based on the propagation parameters isdiscussed in more detail below in regards in FIG. 4 .

While FIG. 2A only shows two ultrasonic transducers transmitting andFIG. 2B only shows three ultrasonic transducers transmitting, in someother examples, five, ten, fifteen, fifty, one hundred, three hundred,or some other number of hundreds of transducers may simultaneouslytransmit ultrasonic signals.

FIG. 3 is a diagram showing an example of a sea lice treatment system300. The system 300 is shown in an open water environment. Nets 301 and302 are used in this implementation to direct fish into a sea licetreatment station 304. The system 300 includes the nets 301 and 302, thesea lice treatment station 304, a fish 311 (shown in three stages as 311a, 311 b and 311 c), a tube 312 feeding into the sea lice treatmentstation 304, and a weight 314 that provides stability to the sea licetreatment station 304.

The sea lice treatment station 304 is another implementation of the sealice treatment station 102 shown in FIG. 1 and FIGS. 2A and 2B. The sealice treatment station 304 similarly includes a camera and ultrasonictransducers.

FIG. 3 is shown in three stages. Stage A corresponds to the fish 311 aentering the tube 312. Stage B corresponds to the fish 311 b within thesea lice treatment station 304 being treated for sea lice. Stage Ccorresponds to the fish 311 c exiting the sea lice treatment station 102through the tube 312.

Stage A of FIG. 3 shows the fish 311 a entering the tube 312 from thenet 301 enclosure. Other fish are within the net 301. In general, thereis no limit to the number of fish able to be processed by the sea licetreatment station 304.

Stage B of FIG. 3 shows the fish 311 b within the sea lice treatmentstation 304 being treated for sea lice. The fish 311 b is arepresentation of the fish 311 a shown at a later time in a differentlocation. The sea lice treatment station 304 uses a control unit similarto the control unit 112 of FIG. 1 to calibrate ultrasonic signals,detect sea lice, and treat for sea lice.

Stage C of FIG. 3 shows the fish 311 c exiting the sea lice treatmentstation 102 through the tube 312. An incentive can be used to move thefish from the tube 312 to the net 302. Depending on implementation, theincentive can include food or physical forces such as water currents.

In some implementations, the sea lice treatment system 300 can befloating within a body of water. For example, the sea lice treatmentsystem 300 can be submerged within a body of water containing one ormore fish. The one or more fish contained within the body of water maybe processed by the sea lice treatment system 300.

FIG. 4 is a flow diagram illustrating an example of a process 400 forself-calibrating ultrasonic removal of sea lice. Briefly, and as will bedescribed in more detail below, the process 400 includes generating, bytransducers distributed in a sea lice treatment station, a first set ofultrasonic signals, detecting a second set of ultrasonic signals inresponse to propagation of the first set of ultrasonic signals throughwater, determining propagation parameters of the sea lice treatmentstation based on the second set of ultrasonic signals that weredetected, obtaining an image of a sea louse on a fish in the sea licetreatment station, determining, from the image, a location of the sealouse in the sea lice treatment station, and generating a third set ofultrasonic signals that focuses energy at the sea louse.

The process 400 includes generating, by transducers distributed in a sealice treatment station, a first set of ultrasonic signals (402). Forexample, the ultrasound calibrator may control the ultrasonictransducers 106 to generate ultrasonic signals.

The process 400 includes detecting a second set of ultrasonic signals inresponse to propagation of the first set of ultrasonic signals throughwater (404). For example, the ultrasound calibrator may control theultrasonic transducers 106 to detect for ultrasonic signals.

In some implementations, detecting, by the ultrasonic transducers, asecond set of ultrasonic signals in response to propagation of the firstset of ultrasonic signals through water includes detecting, by a firstultrasonic transducer, ultrasonic signals in response to propagation ofa first ultrasonic signal that was generated by a second ultrasonictransducer and detecting, by the first ultrasonic transducer, ultrasonicsignals in response to propagation of a second ultrasonic signal thatwas generated by a third ultrasonic transducer after the firstultrasonic signal was generated. For example, while calibrating, theultrasound calibrator may generate an ultrasonic signal with one of theultrasonic transducers 106, detect for the ultrasonic signal at all ofthe ultrasonic transducers 106, and then repeat both steps for each ofthe ultrasonic transducers 106.

In some implementations, instead of generating ultrasonic signalssequentially during calibration as described above, the ultrasoundcalibrator may generate ultrasonic signals in parallel. For example, theultrasound calibrator may use the standing wave approach and usevariable coded phase shifts to differentiate which signals are comingfrom which transducers without needing to run one at a time. If usingthe pulsed approach, the ultrasound calibrator may use a similarencoding technique such as pulse width modulation or pulse densitymodulation that differentiates each transmitter so receivers can tellthem apart.

The process 400 includes determining propagation parameters of the sealice treatment station based on the second set of ultrasonic signalsthat were detected (406). For example, the ultrasound calibrator maydetermine propagation parameters of the sea lice treatment station 102based on what ultrasonic signals were generated at the ultrasonictransducers 106 and resultant ultrasonic signals detected at theultrasonic transducers 106.

In some implementations, determining propagation parameters of the sealice treatment station based on the second set of ultrasonic signalsthat were detected includes determining at least one of pulse width ofultrasonic signals of the second set of ultrasonic signals, time offsetsbetween detections of the second set of ultrasonic signals andgeneration of the first set of ultrasonic signals, spectral width, phaseoffset, or reflections of the first set of ultrasonic signals. Forexample, the ultrasound calibrator may determine the millisecondsbetween when an ultrasonic signal is generated at a first transducer andthe ultrasonic signal is detected at a second transducer. In someimplementations, determining propagation parameters may includedetermining precise transducer locations.

The process 400 includes obtaining an image of a sea louse on a fish inthe sea lice treatment station (408). For example, the sea lice detectormay receive an image captured by the camera 104, where the image showsthe fish 109 inside the sea lice treatment station 102.

The process 400 includes determining, from the image, a location of thesea louse in the sea lice treatment station (410). For example, the sealice detector may use object recognition to detect a sea louse on a tailof the fish 109, where the sea louse is detected to be in an exactmiddle of the water containing portion of the sea lice treatment station102.

The process 400 includes generating a third set of ultrasonic signalsthat focuses energy at the sea louse (412). For example, the sea licetreatment controller may control the ultrasonic transducers 160 togenerate ultrasonic signals that focus energy at the exact middle of thewater in the sea lice treatment station 102.

In some implementations, generating a third set of ultrasonic signalsthat focuses energy at the sea louse includes determining, from theimage, that a portion of the fish is not between a particular ultrasonictransducer and the sea louse, generating an ultrasonic signal of thethird set of ultrasonic signals with the particular ultrasonictransducer. For example, from the perspective shown in FIG. 2A, the sealice detector may determine that a sea lice is on the left side of thefish 109 which is directly in line of sight of the ultrasonic transducer106 k and, in response, determine to use the ultrasonic transducer 106 kto generate one of the ultrasonic signals in the set of ultrasonicsignals used to remove a sea louse.

In some implementations, generating a third set of ultrasonic signalsthat focuses energy at the sea louse includes determining, from theimage, that a portion of the fish is between a particular ultrasonictransducer and the sea louse and based on determining, from the image,that the portion of the fish is between the particular ultrasonictransducer and the sea louse, determining not to generate an ultrasonicsignal with the particular ultrasonic transducer. For example, theperspective shown in FIG. 2A, the sea lice detector may determine that asea lice is on a left side of the fish 109 which is blocked from line ofsight of the ultrasonic transducer 106 n by the fish 109 and, inresponse, determine not to use the ultrasonic transducer 106 n togenerate any of the ultrasonic signals in the set of ultrasonic signalsused to remove a sea louse.

In some implementations, generating, by the ultrasonic transducers andbased on the propagation parameters and the location of the sea louse inthe sea lice treatment station, a third set of ultrasonic signals thatfocuses energy at the sea louse includes determining phases ofcontinuous wave ultrasonic signals in the third set of ultrasonicsignals. For example, the ultrasonic signals may be continuous waveswhich vary in phase and period.

In some implementations, the process 400 includes generating, by theultrasonic transducers and based on the propagation parameters and thelocation of the sea louse in the sea lice treatment station a third setof ultrasonic signals that focuses energy at the sea louse, includesdetermining time delays of pulsed ultrasonic signals in the third set ofultrasonic signals. For example, the ultrasonic signals may be pulsessent with different time delays.

In some implementations, the process 400 includes obtaining sensor datafrom at least one of a water temperature sensor, a water pressuresensor, or a water salinity sensor, where determining propagationparameters of the sea lice treatment station is based on the sensor dataand the second set of ultrasonic signals that were detected. Forexample, the ultrasound calibrator may use a current water temperatureof 70° F. sensed by chemical properties of a thermometer to determinepropagation parameters for other temperatures of water.

In some implementations, the process 400 includes determining thatultrasonic signals generated by a particular ultrasonic transducersatisfy self-cleaning criteria, and based on determining that ultrasonicsignals generated by the particular ultrasonic transducer satisfyself-cleaning criteria, generating, by the ultrasonic transducers, afourth set of ultrasonic signals that focus energy at the particularultrasonic transducer. For example, the ultrasonic calibrator maydetermine that ultrasonic signals emitted by a particular transducer aresensed by other transducers as weaker than typical and, in response,determine that dirt, bio-foul, growth, or some other substance on theparticular transducer might be interfering with signals from theparticular transducer so direct energy at the particular transducer toattempt to remove dirt. In another example, the sea lice detector mayvisually determine that a particular transducer looks dirty in an imageand, in response, direct energy at the particular transducer to attemptto remove dirt.

In some implementations, the process 400 includes determining that thesea louse is located near a particular part of a fish and determiningultrasonic signals accordingly. For example, the sea lice treatmentcontroller may determine that the sea louse is within one centimeter ofan eye of a fish or gills and, in response, determine not to generateultrasonic signals to remove the sea louse to protect the sensitive eyeor gills area. FIG. 5 is a diagram 500 showing a sensitive area 510around an eye and gills of fish.

In another example, the sea lice treatment controller may determine thatthe sea louse is on a dorsal fin and, in response, determine to targetthe maximum energy limit that is safe for fish at the sea louse. Forexample, tough skin on the fish's spine may withstand stronger pressuresfrom the ultrasonic transducers than more sensitive portions, near gillsor eyes for example, which may require gentler pressures.

In some implementations, the process 400 includes determining thatanother fish is located between the sea louse and an ultrasonictransducer. For example, the sea lice treatment controller may determinefrom an image captured by the camera 104 that a second fish is betweenthe ultrasonic transducer 106 k and the sea louse on a first fish and,in response, determine to generate a set of ultrasonic signals thatfocuses energy at the sea louse without transmitting from the ultrasonictransducer 106 k as signals from the ultrasonic transducer 106 k areexpected to be blocked by the second fish. In another example, the sealice treatment controller may determine from an image captured by thecamera 104 that no other fish is between the ultrasonic transducer 106 kand the sea louse on a first fish and, in response, determine thatultrasonic signals may be generated by ultrasonic transducer 106 k asultrasonic signals generated by the ultrasonic transducer 106 k are notexpected to be blocked by any other fish.

In some implementations, the process 400 includes determining thatanother fish is located in a particular location and, in response,determining to generate ultrasonic signals that do not generate a sidelobe where ultrasonic energy is focused at the particular location. Forexample, the sea lice treatment controller may determine from an imagecaptured by the camera 104 that a second fish is in a corner of the sealice treatment station 102 and, in response, determine to generateultrasonic signals that keep ultrasonic energy at the corner below anenergy threshold while focusing energy on a sea louse attached to afirst fish.

In some implementations, a second process for self-calibratingultrasonic removal of sea lice may, similarly to process 400, generate afirst set of ultrasonic signals, detect a second set of ultrasonicsignals, and determine propagation parameters. The second process maythen store the propagation parameters for later treatment of sea lice.For example, the sea lice treatment station 102 may perform the secondprocess during stage A, and then store the propagation parameters.

A third process for self-calibrating ultrasonic removal of sea lice may,similarly to process 400, obtain an image of a sea louse and determine alocation of the sea louse. The third process may then access propagationparameters previously stored. For example, the sea lice treatmentstation 102 may receive and store propagation parameters determined fromsome other device, and later access the propagation parameters fromstorage. The third process may continue with similarly generating a setof ultrasonic signals that focuses energy at the sea louse.

In some implementations, a fourth process for self-calibratingultrasonic removal of sea lice may not focus energy at a detected sealouse. For example, similarly to process 400, the fourth process maygenerate a first set of ultrasonic signals, detect a second set ofultrasonic signals, and determine propagation parameters. However,instead of obtaining an image of a sea louse, the fourth process mayinstead detect the presence, location, size, and orientation of fishbased on changes in ultrasonic signals sensed by the ultrasonictransducers 106 and then, without attempting to detect sea lice on thefish, transmit ultrasonic signals with the ultrasonic transducers 106according to the propagation parameters that target a predeterminedamount of ultrasonic energy at the adipose and dorsal fins.

In some implementations, the detection of sea lice can include specificspecies or stages of sea lice. For example, the several species of sealice may include ectoparasitic copepods of the genera Lepeophtheirus andCaligus. The type of fish being analyzed can affect the process of sealice detection. For example, upon detection of a salmon, a system canadapt a system of detection for the detection of Lepeophtheirussalmonis—a species of sea lice which can be especially problematic forsalmon. In some implementations, a detection of a specific species ofsea lice can be separated from other sea lice detections. For example,detection of Lepeophtheirus salmonis can be treated separately fromdetections of Caligus curtis and Lepeophtheirus hippoglossi.

While implementations are described above in the context of sea liceremoval on salmon, self-calibrating ultrasonic removal may also be usedto remove sea lice from other fish, or other ectoparasites from fish.For example, the sea lice treatment station 102 may remove sea lice fromsea trout or three-spined stickleback, or remove Benedenia seriolae, anectoparasitic flatworm that suctions onto yellowtail fish. Accordingly,the sea lice treatment system 100 may also be referred to as anectoparasite treatment system, the sea lice detector may also bereferred to as an ectoparasite detector, the sea lice treatmentcontroller may also be referred to as an ectoparasite treatmentcontroller, and references to sea lice and sea louse described above inregards to FIG. 4 and the first through fourth processes may be replacedwith references to ectoparasites other than sea lice or more generallyectoparasites.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure. For example, various formsof the flows shown above may be used, with steps re-ordered, added, orremoved.

Embodiments of the invention and all of the functional operationsdescribed in this specification can be implemented in digital electroniccircuitry, or in computer software, firmware, or hardware, including thestructures disclosed in this specification and their structuralequivalents, or in combinations of one or more of them. Embodiments ofthe invention can be implemented as one or more computer programproducts, e.g., one or more modules of computer program instructionsencoded on a computer readable medium for execution by, or to controlthe operation of, data processing apparatus. The computer readablemedium can be a machine-readable storage device, a machine-readablestorage substrate, a memory device, a composition of matter affecting amachine-readable propagated signal, or a combination of one or more ofthem. The term “data processing apparatus” encompasses all apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, or multiple processors or computers.The apparatus can include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them. A propagated signal is an artificially generated signal, e.g.,a machine-generated electrical, optical, or electromagnetic signal thatis generated to encode information for transmission to suitable receiverapparatus.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Moreover, a computer can be embedded inanother device, e.g., a tablet computer, a mobile telephone, a personaldigital assistant (PDA), a mobile audio player, a Global PositioningSystem (GPS) receiver, to name just a few. Computer readable mediasuitable for storing computer program instructions and data include allforms of non volatile memory, media and memory devices, including by wayof example semiconductor memory devices, e.g., EPROM, EEPROM, and flashmemory devices; magnetic disks, e.g., internal hard disks or removabledisks; magneto optical disks; and CD ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,special purpose logic circuitry.

To provide for interaction with a user, embodiments of the invention canbe implemented on a computer having a display device, e.g., a CRT(cathode ray tube) or LCD (liquid crystal display) monitor, fordisplaying information to the user and a keyboard and a pointing device,e.g., a mouse or a trackball, by which the user can provide input to thecomputer. Other kinds of devices can be used to provide for interactionwith a user as well; for example, feedback provided to the user can beany form of sensory feedback, e.g., visual feedback, auditory feedback,or tactile feedback; and input from the user can be received in anyform, including acoustic, speech, or tactile input.

Embodiments of the invention can be implemented in a computing systemthat includes a back end component, e.g., as a data server, or thatincludes a middleware component, e.g., an application server, or thatincludes a front end component, e.g., a client computer having agraphical user interface or a Web browser through which a user caninteract with an implementation of the invention, or any combination ofone or more such back end, middleware, or front end components. Thecomponents of the system can be interconnected by any form or medium ofdigital data communication, e.g., a communication network. Examples ofcommunication networks include a local area network (“LAN”) and a widearea network (“WAN”), e.g., the Internet.

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of the invention or of what may beclaimed, but rather as descriptions of features specific to particularembodiments of the invention. Certain features that are described inthis specification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Particular embodiments of the invention have been described. Otherembodiments are within the scope of the following claims. For example,the steps recited in the claims can be performed in a different orderand still achieve desirable results.

What is claimed is:
 1. A computer-implemented method, comprising:generating, by ultrasonic transducers distributed in a sea licetreatment station, a first set of ultrasonic signals; detecting, by theultrasonic transducers, a second set of ultrasonic signals in responseto propagation of the first set of ultrasonic signals through water inthe sea lice treatment station; determining propagation parameters ofthe sea lice treatment station based on the second set of ultrasonicsignals that were detected; and storing the propagation parameters forlater treatment of sea lice.
 2. The method of claim 1, whereindetecting, by the ultrasonic transducers, a second set of ultrasonicsignals in response to propagation of the first set of ultrasonicsignals through water in the sea lice treatment station comprises:detecting, by a first ultrasonic transducer, ultrasonic signals inresponse to propagation of a first ultrasonic signal that was generatedby a second ultrasonic transducer; and detecting, by the firstultrasonic transducer, ultrasonic signals in response to propagation ofa second ultrasonic signal that was generated by a third ultrasonictransducer after the first ultrasonic signal was generated.
 3. Themethod of claim 1 wherein determining propagation parameters of the sealice treatment station based on the second set of ultrasonic signalsthat were detected comprises: determining at least one of: width ofultrasonic signals of the second set of ultrasonic signals, time offsetsbetween detections of the second set of ultrasonic signals andgeneration of the first set of ultrasonic signals, or reflections of thefirst set of ultrasonic signals.
 4. The method of claim 1 whereindetermining propagation parameters of the sea lice treatment stationbased on the second set of ultrasonic signals that were detectedcomprises: determining time delays of pulsed ultrasonic signals in theset of ultrasonic signals.
 5. The method of claim 1, comprisingobtaining sensor data from at least one of a water temperature sensor, awater pressure sensor, or a water salinity sensor, wherein determiningpropagation parameters of the sea lice treatment station is based on thesensor data and the second set of ultrasonic signals that were detected.6. The method of claim 1, wherein generating by ultrasonic transducersdistributed in a sea lice treatment station, a first set of ultrasonicsignals comprises: determining, that a portion of the fish is notbetween a particular ultrasonic transducer and the sea lice treatmentstation; and based on determining that a portion of the fish is notbetween a particular ultrasonic transducer and the sea lice treatmentstation, generating an ultrasonic signal of the first set of ultrasonicsignals with the particular ultrasonic transducer.
 7. The method ofclaim 1, wherein storing the propagation parameters for later treatmentof sea lice comprises: storing propagation parameters for each of theultrasonic transducers.
 8. A computer-implemented method, comprising:obtaining an image of a sea louse on a fish in a sea lice treatmentstation; determining, from the image, a location of the sea louse in thesea lice treatment station; accessing propagation parameters of the sealice treatment station from storage of the sea lice treatment station;and generating, by ultrasonic transducers of the sea lice treatmentstation and based on the propagation parameters and the location of thesea louse in the sea lice treatment station, a third set of ultrasonicsignals that focuses energy at the sea louse.
 9. The method of claim 8,wherein generating a third set of ultrasonic signals that focuses energyat the sea louse comprises: determining, from the image, that a portionof the fish is not between a particular ultrasonic transducer and thesea louse; and based on determining, from the image, that the portion ofthe fish is not between the particular ultrasonic transducer and the sealouse, generating an ultrasonic signal of the third set of ultrasonicsignals with the particular ultrasonic transducer.
 10. The method ofclaim 8, wherein generating a third set of ultrasonic signals thatfocuses energy at the sea louse comprises: determining, from the image,that a portion of the fish is between a particular ultrasonic transducerand the sea louse; and based on determining, from the image, that theportion of the fish is not between the particular ultrasonic transducerand the sea louse, determining not to generate an ultrasonic signal withthe particular ultrasonic transducer.
 11. A non-transitory computerstorage medium encoded with instructions that, when executed by one ormore computers, cause the one or more computers to perform operationscomprising: generating, by ultrasonic transducers distributed in a sealice treatment station, a first set of ultrasonic signals; detecting, bythe ultrasonic transducers, a second set of ultrasonic signals inresponse to propagation of the first set of ultrasonic signals throughwater in the sea lice treatment station; determining propagationparameters of the sea lice treatment station based on the second set ofultrasonic signals that were detected; and storing the propagationparameters for later treatment of sea lice.
 12. The computer storagemedium of claim 11, wherein detecting, by the ultrasonic transducers, asecond set of ultrasonic signals in response to propagation of the firstset of ultrasonic signals through water in the sea lice treatmentstation comprises: detecting, by a first ultrasonic transducer,ultrasonic signals in response to propagation of a first ultrasonicsignal that was generated by a second ultrasonic transducer; anddetecting, by the first ultrasonic transducer, ultrasonic signals inresponse to propagation of a second ultrasonic signal that was generatedby a third ultrasonic transducer after the first ultrasonic signal wasgenerated.
 13. The computer storage medium of claim 11 whereindetermining propagation parameters of the sea lice treatment stationbased on the second set of ultrasonic signals that were detectedcomprises: determining at least one of: width of ultrasonic signals ofthe second set of ultrasonic signals, time offsets between detections ofthe second set of ultrasonic signals and generation of the first set ofultrasonic signals, or reflections of the first set of ultrasonicsignals.
 14. The computer storage medium of claim 11 wherein determiningpropagation parameters of the sea lice treatment station based on thesecond set of ultrasonic signals that were detected comprises:determining time delays of pulsed ultrasonic signals in the set ofultrasonic signals.
 15. The computer storage medium of claim 11,comprising obtaining sensor data from at least one of a watertemperature sensor, a water pressure sensor, or a water salinity sensor,wherein determining propagation parameters of the sea lice treatmentstation is based on the sensor data and the second set of ultrasonicsignals that were detected.
 16. The computer storage medium of claim 11,wherein generating by ultrasonic transducers distributed in a sea licetreatment station, a first set of ultrasonic signals comprises:determining, that a portion of the fish is not between a particularultrasonic transducer and the sea lice treatment station; and based ondetermining that a portion of the fish is not between a particularultrasonic transducer and the sea lice treatment station, generating anultrasonic signal of the first set of ultrasonic signals with theparticular ultrasonic transducer.
 17. The computer storage medium ofclaim 11, wherein storing the propagation parameters for later treatmentof sea lice comprises: storing propagation parameters for each of theultrasonic transducers.
 18. A non-transitory computer storage mediumencoded with instructions that, when executed by one or more computers,cause the one or more computers to perform operations comprising:obtaining an image of a sea louse on a fish in a sea lice treatmentstation; determining, from the image, a location of the sea louse in thesea lice treatment station; accessing propagation parameters of the sealice treatment station from storage of the sea lice treatment station;and generating, by ultrasonic transducers of the sea lice treatmentstation and based on the propagation parameters and the location of thesea louse in the sea lice treatment station, a third set of ultrasonicsignals that focuses energy at the sea louse.
 19. The computer storagemedium of claim 18, wherein generating a third set of ultrasonic signalsthat focuses energy at the sea louse comprises: determining, from theimage, that a portion of the fish is not between a particular ultrasonictransducer and the sea louse; and based on determining, from the image,that the portion of the fish is not between the particular ultrasonictransducer and the sea louse, generating an ultrasonic signal of thethird set of ultrasonic signals with the particular ultrasonictransducer.
 20. The computer storage medium of claim 18, whereingenerating a third set of ultrasonic signals that focuses energy at thesea louse comprises: determining, from the image, that a portion of thefish is between a particular ultrasonic transducer and the sea louse;and based on determining, from the image, that the portion of the fishis not between the particular ultrasonic transducer and the sea louse,determining not to generate an ultrasonic signal with the particularultrasonic transducer.